A teen (Lou Taylor Pucci) rebels through rock in this well-made family drama.

A middle-aged father – extremely well- played by character actor J.K. Simmons — reluctantly uses rock music to repair his relationship with a brain-damaged son in the unpretentious and unexpectedly moving “The Music Never Stops.”

While it’s also based on a case study by famed neurologist Oliver Sacks, debuting director Jim Kohlberg’s modest drama mercifully avoids the histrionics of Penny Marshall’s overblown and schmaltzy “Awakenings” (1990), which starred an Oscar-baiting Robin Williams as a Sacks surrogate and Robert De Niro as a patient he aroused from decades of catatonia.

In this movie, set primarily in 1989, Simmons plays a conservative engineer whose life is upended when authorities find his 35-year-old son (Lou Taylor Pucci), whom he hasn’t seen in nearly 20 years. The young man has been hospitalized with a massive tumor; even when it’s removed, he can’t remember anything after 1970, and can’t form any new memories.

Then a speech therapist (Julia Ormond) recruited by the father — who’s become so distracted he loses his job — establishes that the minimally responsive patient comes briefly to life when he hears familiar rock music from the ’60s.

This puts the old man, whose tastes run to the big-band era, in a difficult position: As we see in flashbacks, it’s this very rock music that he blames for his rebellious son leaving their suburban home for Greenwich Village, not to be seen for years.

It sounds like TV-grade schmaltz (I didn’t even mention that the father has a bad heart), but it isn’t, thanks to expertly astringent work by Simmons, perhaps best-known as the understanding dad in “Juno.”

The 25-year-old Pucci seems more comfortable in the ’60s flashbacks than in the 1989 scenes, which require him to play a childlike character a decade older than his actual age. But there is an oddly touching scene when the older character asks an ex-girlfriend about an acquaintance who turns out to have died in Vietnam.

“The Music Never Stopped,” which has a most impressive soundtrack for a low-budget indie, is in the end more about music than politics. I have to admit misting up when father and son attend their first Grateful Dead concert together.